1. Field of the Invention
The present invention relates to a fluid-filled vibration damping device used for an automobile engine mount or the like.
2. Description of the Related Art
From the past, a fluid-filled vibration damping device has been known which is interposed between members constituting a vibration transmission system, which is one type of vibration damping support unit or vibration damping coupling unit which does mutual vibration damping connection of those members. The fluid-filled vibration damping device has a first mounting member and a second mounting member elastically connected by a main rubber elastic body, and has a constitution whereby a fluid chamber is formed for which a portion of the wall part is constituted by a main rubber elastic body, and in which a non-compressible fluid is sealed.
Incidentally, with the fluid-filled vibration damping device, for example, as shown in Japanese Unexamined Patent Publication No. JP-A-2000-266105, an outer bracket is mounted on a vibration damping device main unit equipped with a fluid chamber in which non-compressible fluid is sealed, and generally, the sealing property of the fluid chamber is ensured with the vibration damping device main unit alone before mounting of the outer bracket.
However, when trying to ensure fluid tightness of the fluid chamber with the vibration damping device main unit alone, it is necessary to use large axial dimensions for the second mounting member for providing a seal structure, and it was difficult to make the vibration damping device main unit more compact in the axial direction. Furthermore, when an attempt is made to constitute a seal structure of the fluid chamber by doing press fitting or the like of a flexible film fixing ring on the second mounting member in a tank filled with non-compressible fluid, dimensional accuracy of the second mounting member and fixing ring are required, and there was the problem that the assembly work was difficult.
In French Patent Publication No. FR 2810712, disclosed is a fluid-filled vibration damping device made to have a fluid tight sealed fluid chamber by separately attaching the integrally vulcanized molded component of the main rubber elastic body and the flexible film to the outer bracket.
However, with the constitution of FR 2810712, as was performed with the prior art fluid-filled vibration damping device, when an attempt is made to seal non-compressible fluid in the fluid chamber by assembling in a tank filled with non-compressible fluid, it is necessary to do work with a large size and large mass outer bracket formed by aluminum alloy or the like placed in a tank, and there is the risk of problems such as the assembly process being difficult, productivity decreasing, or the like.
Also, in Japanese Patent No. JP-B-4113889, disclosed is a hydraulic damping bearing for which a bellows, bulkhead, and elastic support body are joined by hooking and engaging a bearing cover on an elastic support body, and a sealing structure filled with damping fluid is completed.
However, to realize a sealing structure filled with damping fluid simply by hooking and engaging of the bearing cover, to exhibit sufficient sealing function, great strength is required for the hook engagement. To do that, when engaging the hook part provided on the bearing cover on the elastic support body, in addition to force being needed to strongly compress the sealing rubber, at the same time, large force is needed to deform the high strength hook part and engage it on the elastic support body, so there was still room for improvement from the manufacturing aspect.